CVE-2025-40287 (GCVE-0-2025-40287)

Vulnerability from cvelistv5 – Published: 2025-12-06 21:51 – Updated: 2026-05-11 21:46
VLAI
Title
exfat: fix improper check of dentry.stream.valid_size
Summary
In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 11a347fb6cef62ce47e84b97c45f2b2497c7593b , < 6c627bcc1896ba62ec793d0c00da74f3c93ce3ad (git)
Affected: 11a347fb6cef62ce47e84b97c45f2b2497c7593b , < 204b1b02ee018ba52ad2ece21fe3a8643d66a1b2 (git)
Affected: 11a347fb6cef62ce47e84b97c45f2b2497c7593b , < 82ebecdc74ff555daf70b811d854b1f32a296bea (git)
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Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.12.59 , ≤ 6.12.* (semver)
Unaffected: 6.17.9 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
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          "product": "Linux",
          "programFiles": [
            "fs/exfat/namei.c"
          ],
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              ],
              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nexfat: fix improper check of dentry.stream.valid_size\n\nWe found an infinite loop bug in the exFAT file system that can lead to a\nDenial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is\nmalformed, the following system calls \u2014 SYS_openat, SYS_ftruncate, and\nSYS_pwrite64 \u2014 can cause the kernel to hang.\n\nRoot cause analysis shows that the size validation code in exfat_find()\ndoes not check whether dentry.stream.valid_size is negative. As a result,\nthe system calls mentioned above can succeed and eventually trigger the DoS\nissue.\n\nThis patch adds a check for negative dentry.stream.valid_size to prevent\nthis vulnerability."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:46:25.955Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/6c627bcc1896ba62ec793d0c00da74f3c93ce3ad"
        },
        {
          "url": "https://git.kernel.org/stable/c/204b1b02ee018ba52ad2ece21fe3a8643d66a1b2"
        },
        {
          "url": "https://git.kernel.org/stable/c/82ebecdc74ff555daf70b811d854b1f32a296bea"
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      ],
      "title": "exfat: fix improper check of dentry.stream.valid_size",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40287",
    "datePublished": "2025-12-06T21:51:13.328Z",
    "dateReserved": "2025-04-16T07:20:57.184Z",
    "dateUpdated": "2026-05-11T21:46:25.955Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-10-30",
      "epss": "0.00185",
      "percentile": "0.08144"
    },
    "microsoft_vex": {
      "current_release_date": "2025-12-09T01:40:07.000Z",
      "cve": "CVE-2025-40287",
      "id": "msrc_CVE-2025-40287",
      "initial_release_date": "2025-12-02T00:00:00.000Z",
      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "exfat: fix improper check of dentry.stream.valid_size",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-40287.json",
      "version": "3"
    },
    "nvd": {
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                "product": "Linux",
                "programFiles": [
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nexfat: fix improper check of dentry.stream.valid_size\n\nWe found an infinite loop bug in the exFAT file system that can lead to a\nDenial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is\nmalformed, the following system calls \u2014 SYS_openat, SYS_ftruncate, and\nSYS_pwrite64 \u2014 can cause the kernel to hang.\n\nRoot cause analysis shows that the size validation code in exfat_find()\ndoes not check whether dentry.stream.valid_size is negative. As a result,\nthe system calls mentioned above can succeed and eventually trigger the DoS\nissue.\n\nThis patch adds a check for negative dentry.stream.valid_size to prevent\nthis vulnerability."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nexfat: corrige la comprobaci\u00f3n incorrecta de dentry.stream.valid_size\n\nHemos encontrado un error de bucle infinito en el sistema de archivos exFAT que puede conducir a una condici\u00f3n de Denegaci\u00f3n de Servicio (DoS). Cuando una dentry en un sistema de archivos exFAT est\u00e1 malformada, las siguientes llamadas al sistema - SYS_openat, SYS_ftruncate y SYS_pwrite64 - pueden hacer que el kernel se cuelgue.\n\nEl an\u00e1lisis de la causa ra\u00edz muestra que el c\u00f3digo de validaci\u00f3n de tama\u00f1o en exfat_find() no comprueba si dentry.stream.valid_size es negativo. Como resultado, las llamadas al sistema mencionadas anteriormente pueden tener \u00e9xito y eventualmente desencadenar el problema de DoS.\n\nEste parche a\u00f1ade una comprobaci\u00f3n para dentry.stream.valid_size negativo para prevenir esta vulnerabilidad."
          }
        ],
        "id": "CVE-2025-40287",
        "lastModified": "2026-10-15T19:10:00.173",
        "metrics": {},
        "published": "2025-12-06T22:15:56.927",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
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      "current_release_date": "2026-06-30T10:19:49+00:00",
      "cve": "CVE-2025-40287",
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      "product_status:known_affected": "184",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: exfat: fix improper check of dentry.stream.valid_size",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40287.json",
      "version": "3"
    }
  }
}



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